I think scam is so widespread and not everybody go to scam accusation board so it is quite fair that you attack against them in there ANN + Bounty thread.
Nothing should be considered Off-Topic when somebody is giving warning against scam.

Mods might have deleted it because it is just an accusation without a proof. Might be if you included the proof and challenged the tread creator to reply in Scam accusation board  then I do not think they will delete it.

The post that is deleted simply look accusation/threat without any proof and I think Mods are right.